If you’ve just completed your HD install, whether 1080i or 720p, you’re probably hearing about 1080p/50 — the next step in HD — all the time. Presently, there aren’t many ways to get this super-resolution content.
You can buy a BluRay player that will play 1080p/50 content. Just be sure you get a 1080p disc! And you can certainly invest in a 1080p/50 projector or other display.
But there’s an even better reason for you to start shooting material in 1080p and that is compatibility between 1080i and 720p. Murphy’s Law says that if you shoot in 1080i, your customer will want 720p. And if you shoot in 720p, your customer will want 1080i.
Transcoding between these two formats is not easy, especially with high-motion video such as race tracks or sports video. The solution is to shoot in 1080p/50 that can be down-resolved to 1080i or 720p with no artifacts.
Also, this would allow you to sell your material a second time when 1080p becomes a common distribution or broadcast format.
So how can you be prepare for 1080p/50? Well, first, don’t confuse this with 1080p/25 or another format that uses slower frame-rates. That’s the same data rate as 1080i, and the slower frame rate only increases motion-based artifacts.
Every major professional camera manufacturer has a 1080p/50 cam or option for an existing cam. Be aware that the bit stream for 1080p/50 is twice that of 1080i or 720p, so you’re going to burn through tape or disc or whatever recording form you intend to use.
If you buy larger storage or recording media, it’s not cheap. Even if you are in the studio and recording directly onto a server somewhere, you will be amazed at how fast you can fill a terabyte.
And then you have the little problem of cable. This 1080p/50 is double the bandwidth of regular HD, so where the occupied bandwidth of HD is 750 MHz, it is 1.5 GHz for 1080p/50. And you need to look at a bandwidth wider than the signal to be sure you’ve passed all your data.
The standard rule is to look at the third harmonic. For HD, this means you look at 2.25 GHz. Many companies manufacture and test cable to the fourth harmonic (3 GHz) for even greater assurance.
The problem is that the third harmonic of 1080p bandwidth is 1.5 GHz x 3 = 4.5 GHz. And there is no standard test gear that will measure 75 ohms out to 4.5 GHz. There could be but nobody has asked for it before.
Only one cable manufacturer (Belden) has had custom-built and NIST traceable matching networks made for 4.5 GHz at 75 ohms – a huge expense for a signal (1080p/50) that is more promise than practice.
Of course, with any cable installation, the real question is not what are you going to use it for today, but what might you be doing next year? Pulling out and re-installing cable is, at the very least, a waste of money and labour, so why not put in 1080p/50 cable now?
The only thing you need to consider is that the distance on cables is less at 1080p/50 than at HD. Table 1 below shows some standard cables with the HD and 1080p/50 distances.
Luckily, as you can see, it’s a little better than half the HD distance..
This might make you think about what size cable and what cable distance you intend to use. If you design your install to the 1080p/50 suggested lengths above, then you will not need to rewire when you begin to add 1080p/50 equipment.
Steve Lampen is Multimedia Technology Manager and Product Line Manager for Audio-Video-Broadcast products at Belden.
Percon breaks the limits of the 3G-SDI standard
Percon’s Engineering Department has carried out strict tests on the high definition video cables (3G-SDI) to find out the maximum distance that can reach the 3Gbps signals.
The company claims that the results “are outstanding and exceed the distances offered by other companies in the broadcast field”.
“The tests have been conducted using the Tektronix progressive high definition video signal generator WFM 7120, with a modulation rate of 2.970 Gbps (SMPTE 424/425M) and a screen refresh of 50/59.94/60Hz and Percon’s HDTV BNC connectors.
Percon’s VK9 (1.6/7.1) has reached 220 metres with a signal 3G-SDI (1080p) YCbCr 4:2:2 at 50 and 60 HZ according to SMPTE 424M and SMPTE 425M.
PERCON will also launch a new range of video patch panels for HDTV (HD-SDI) with fibre optic hybrid cable according to the SMPTE 311M (ref. Percon M2F4C) for HD digital video applications.
The patch panel is 2RU high and can be fully customised, giving the possibility to apply different combinations according to every need (up to 6 connectors).
This new product increases the wide range of Percon’s HDTV solutions.
The M2F4C cable is designed under the SMPTE 311M recommendations that define the union of single mode fibre optic and control/signal cables.
It is used in professional video production for simultaneous transmission of video, audio and control between the OB van and the master station.
IBC will see the European debut of Argosy’s BendBright-XS ruggedised fibre optic cables as well as fibre management tools such as its SDI fibre video converters and patch panels.
With its reduced bend radius single mode fibre cable, BendBright provides good resistance to macro bend attenuation allowing it to be handled in the same way as traditional copper cable.
The benefits of this include added versatility, reduced installation time and minimal fibre damage, making BendBright-XS best suited for deployment in confined spaces patch cables, high density areas and outside broadcast vehicles.
Argosy claims that BendBright-XS cable is the first fibre of its kind on the market and is unique in its ability to fulfil all three relevant ITU recommendations — G.652.D, G657.A and G.657.
Argosy also provides a range of single and multi-mode fibres which can be supplied in patch, breakout or in multi-way loose-tube & tight buffered constructions with 4 to 864 fibres as per requirement.
These cables incorporate internal strength members enabling them to be very versatile and suitable for both internal and external applications whilst maintaining a low weight and shorter bend radiuses for ease of installation.
Argosy will also demo its copper-to-fibre media converter, which offers greater distances for the transmission of SDI signals - up to 20km depending on bit-rate being used.
It works by receiving an HD-SDI electrical input and converting this into a single mode optical signal and supports the transmission of SD-SDI (143-540Mb/s) and HD-SDI (1.485Gb/s). Both transmitter and receiver provide automatic equalisation and input re-clocking to ensure signal integrity.
Expect also to see Argosy’s range of IMAGE HD video cables, connectors, fibre optic cables and a wide array of video accessories.